After briefly climbing out of the Hollywood dating pool late last year, Amanda Seyfried has cannonballed back in. Us Weekly says the starlet, 26, whose brief romance with New York real estate exec Andrew Joblon ended in December, has been dating Josh Hartnett since January.

"Josh likes to keep things low-key, so they've just been hanging out " relays a source, who says the pair were set up by a mutual pal.

But Seyfried appears to be smitten with Hartnett, who was the last man to date Katie Holmes before she was sucked into Tom Cruise's mother ship in 2005.

During a double date last month with are-they-or-aren't-they exes Michael C. Hall and Jennifer Carpenter, "She looked into him," notes a spy. Of course, another meet-up with the "Dexter" duo a few days earlier produced a different observation, with an amateur body language expert telling Star, "He really seemed into her."

One thing Seyfried, 26, and Hartnett, 33, are for sure both into: their dogs. Both are frequently photographed walking their four-legged best friends, so at least they have some common ground.

Amanda, who recently told Elle that she's "terrified of being promiscuous," counts Ryan Phillippe and Dominic Cooper among her exes. In addition to Holmes, Hartnett has dated Scarlett Johansson and model Sophia Lie.